Automatic pressure-controlling device for brake mechanisms.



, H; ROWNTREE. AUTOMATIC PRESSURE CONTROLLING DEVICE FOR BRAKEMECHANISMS.

APPLICATION FILED JAN. 19, 1910.

Patented Nov. 29, 1910.

\N N 1 Q Q YR W rt! IIIIIIIIIII I! UNITED STATES PATENT orrron,

HAROLD ROWNTRE OF CHICAGO, ILLINOIS, ASSIGNOR T0 NATIONAL PNEUMATICCOMPANY, A CORPORATION O15 WEST VIRGINIA.

AUTOMATIC IRESSURE-CONTROLLING DEVICE FOR BRAKE MECHANISMS.

Specification of Letters Patent.

Application filed January 19, 1910 Serial No. 538,848.

a specification.

This invention relates to automatic pressure COI1t1Oll]Il devices forbrake mechamsm.

The object of, the invention is to provide means for regula'lting theapplication'of the brake pressure according to the speed of movement-ofthe car.

A further object is to providemeans for :uttomatically controllingtheapplication of the brake pressure proportionately; to the. speed ofmovement of the car. 7 t

A further object is to provide means whereby the maximum pressurepermissible to be applied by the brake mechanism is automatically variedin proportion to the speed of the car.

A further object is to provide means controllable conjointly by thepressure itself and by the speed 'of the car for regulating theapplication of the pressure to the brake mechanism.

Other objects of the invention will appear more fully hereinafter.

The invention consists substantially in the construction, combinationlocation and relative arrangement of parts, all as will be more fullyhereinafter set forth, as shown in the accompanying drawing and finallypointed out in the appended claims.

The drawingshows partly in diagram and, parts in section, an arrangementof automatic pressure controlling mechanism embodying the principles ofmy invention.

In stopping the motion of a car, or of a train by the application of airbrakes it is desirable that the pressure applied shall not increasebeyond a certain point as the application of too great an amount ofpressure will cause the brake shoes to freeze to the wheels and stop thecar or train too suddenly, thereby causing trouble, and fre quentlydisastrous andcven fatal accidents. The amount of pressure permissibleto be applied depends on the speed of the train or car, the faster thetrain or car is moving at i the instant the brakes are applied, thegreater the pressure 'which it is permlssible to apply withoutdanger.I11 the ordinary form of brake control, the motorman or engineer inorder'to stop his car or train, manipulates his control handle to admita fairly heavy pressure to the brake cylinders without knowing themaximum pressure allowable to be applied for the particular speed atwhich the car or train is moving without danger, the amount of pressureso applied being governed only by the judgment and experience of themotorman or engineer. As the car or train slows down unxler thisapplication of pressure the motorman or engineer bleeds the pressure outso as to reduce thesame. It'is among the special purposes of mylnvention to provide means whereby the motorman or engineer -by merelymoving his control handle to a certain position effects an applicationof the maximum degree of pressure permissible without danger according"to the speed at which the car or train happens to be moving at theinstant of such application, and without depending on his own skill,judgment,

discretion or experience, which may be faulty. And I also .propose toprovide means whereby as the car or train diminishes in speed the brakepressure is proportionately and automatically decreased, therebyenabling the train or car to slow down and stop at all times with greatsmoothness, and without. danger of injury, and within a minimumdistance.

' In carrying outmy invention I provide means controlled conjointly bythe pressure Patented Nov. 29, 1910.

medium and the speed at which the car or train is moving, forautomatically regulating the supply of pressure to the brake mechanism.

Many specifically different constructions and arrangements of devicesand. appliances may be devised forcarrying my invention into practicaloperation; While, therefore, I;

the motormans control handle u on which,

is mounted a contact member B, w itch is arranged to make contact with aconductor C, in whatever position to which the handle A, may be moved.The conductor C, is shown one or the other-of the strips Q, Y, accordinthe form of 'a ring concentric with the axis about which the handle Aturns. The conductor 0, is connected through wire a, to

In a small cfylinder G, is arranged a piston H, one side 0 which isexposed to the pressure medium as supplied to the brake mechanism,and'the other side of which is acted -'upon by a spring I,"the tension'of the latter being normally exerted to move the piston H, toward thatend of the cylinder G, which is in communication with the pressuresupply connections to the brake mechanism. The piston H is connectedby'a rod J, to the free end of arock lever K, pivotally'mounted to rockor swing about an, axis L. Mounted concentric with the axis of, or incooperative relation with'respect to lever K, is a member N, which,inthis instance, is in the form ofa rotative disk. This diskis designedto be rotatively displaced to a degree proportionate tothe speed atwhich the car is moving. For this purpose I propose to rotativelyactuatesaid disk from an axle orother convenient running part of the car. Anysuitable form of well known speedometer which is driven froma-rotating'part of the running gear of the'car, and whichrotatively'displaces the disk proportionally to the speed of the carwill answer. A speedmeter such for instance andas illustrative of oneform of embodiment of operative means, for the purpose, as is shown inthe patent to .Weston No. 277,179, dated May 8th, 1883, will serve mypurposes but I do not wish to be limited or restricted in this respect.

By-employing a disk rotatively displaced as above explained, it will beseen that the faster the train or car is traveling the greater will bethe degree of rotative displacement of said disk, the arrow indicatingthe direction of rotative displacement thereof. The disk N has mountedon the face thereof two circular contact strips Q, Y, separated fromeach other and also a contact ring-R; The lever K, carries acontactstrip M, arranged tobri'dge. the space between the ring R and ingto the relative positions of the disk and lever. Bearing against thestrip Q, is a brush or contact 0, and bearing a ainst strip Y, is abrush or contact P. A similar brush or contact S, bears against contactring R. Reference signs. T, U, designate electro-magnets respectivelyarranged to "operate valves 10i111. These valves control the supply andex aust of air to and from the bra ergized the valve 10, is moved fromits seat I thereby admitting the pressure medium from the tank orothersource (not shown) pressure.

e cylinder.- When the magnet T is en;

cylinder, (not shown). When the magnet U, is energized the valve 11, ismoved from its seat thereby opening the brake cylinder to exhaustthrough pipes 12, \V and X. The

pressure connection NV, 12, is also incom-- municatlon with one end ofcylinder Gr, so

that the pressure medium is enabled to act against the inner face of thepiston H.

The brush contacts 0, P, are respectively in electrical connection withcontact points D, F, through wire or other connections 13, 14, and alsothrough wire or other connections 15, 16, with one of the terminals ofthe windings of the electroanagnets U, T,

the other terminals'of the magnet windings position-for the contact B,to make contact with contact point D, the circuit j ust' traced isbroken While another circuit is completed fromthe source ofcurrentthrough the positive supply main a, to contact C, and thencethrough strip 13, contact D, connection 13, brush 0, connection '15, thewindings of magnet U, to the negative'main Z). The re sultingenergization of magnet U, causes valve-l1, to be unseated therebyopening the brake cylinder, cylinder G, pipes 12 and w, to exhaust, andrelieving the brakes of all If now the control handle is shifted intoposition for strip B, to make contact with point F, the circuit from thesource ofenergy is completed from main a throughcontact C, strip B,contact F, connection l4, brush P, connection 16, the windings ofelectro-magnet T, and to thereturn main 6. The resulting energization ofmagnet T, causes valve 10, to be unseated thereby admitting pressure tothe brake mechanism. In this way by suitably .and properly manipulatingthe handle A back or forth from D to F or from F to D, that is to andfrom on and off positions the ap-. plieation of the brakes and thebleeding of the pressure is accomplished in the present usual way. If,however, it is desired to apply the maximum pressure that can be appliedwith safety, the motorman places his control handle in position for thestrip B, to contact with point E. Thereupon the following circuit iscompleted from'the main (1,

throughcontact C, strip B, point E, connection l7, brush S, ring R, andstrip M. -If

the car is in motion at this instant, then thesition, in the-directionindicated y the arstrip Q, brush P, connection 16, magdisk N will be in'rotatively dis laced porow, and 'consequentlytstrip-M,will also be incontact with strip Q, consequently the above-traced circuit willcontinue from strip x 1 net'c pressure will be supplied and thebrakesapplied. As the bra to pressure builds up behind piston H, said pistonis' forced out wardly in cylinder G, against the llCtlOIl; of spring I,thereby moving'rod J, and rocking lever K, in .the' direction of thearrow. When contact M, in this rotat'ivemove'ment of lever K, reachesthe space between the'adof stri s Q,

jacent ends of strips Q, Y, the last traced circuit is broken andthe'magnet T 1s deenergizd, The distance through which the 'lever K- ismoved before the contact M reaches the 8%?(36 between the adjacent endswill of course depend upon the extent to which the disk N has beenrotatively' displaced, and this, in turn, is dependent upon the speed atwhich the car is traveling. As the speed of the car begins to diminishunder the application of the braking pressure, as above described, thedisk N begins its return rotation in a direction 015 osite that ofthe-arrow and. eventually strip-1a, will contact with strip Y, and thenthe circuit from strip M, will be completed through strip Y, brush 0,connection 15, magnet U, to return Y), thereby opening the bra emechanism to exhaust. This will reduce the pressure in cylinder G, andthe piston H,'w1 ll begin its travel unde'rthe influence of spring I,thereby rockin'glever K,

in a direction opposite that indicated by the arrow until the strip Magain reaches the jaa'p between the adjacent ends of strips Y, therebyopening the circuit. If the car still has any headway the disk N willstill be snore or less displaced rotatively in the direction indicatedby the arrow, and

"hence the strip M, will again be brought into contact with strip Q, foranother application'of pressure. This action continues as long as thecontroller handle remains in its central position, that is, in positionfor disk N, as to determine the maximum degree of pressure which wouldbe safe to be applied to the brake for the particular speed "at whichthe car is moving at any given instant. .Thus the piston H, is balancedbetween the brake pressure and the spring I,

and since this balance is controlled by the.

brake pressure and since .the lever K cooperates with the rotatively dislaceable d1sk N, which latter is cbntrolle by the speed of the car, itwill be seen that the dc sired automatic control of the brake pressureis effected through the conjoint action of the pressure and the speed ofthe car, and therefore this control is so regulated that not only is themaximum safe pressure always initially ap lied but also this applicationas well as t e continued application of brake pressure is controlledautomatically so as to remain proportional to the speed of the 'car andall that is required of the motorman is to move his control handle intoposition for strip B, thereon to make contact with point a By the use ofa'brake pressure controlling apparatus such as above described, a car ortrain can be operated at a higher speed between stations or stoppinpoints than heretofor, or at a lower hea way between succ I I 0 I Vceedlng cars or trams, since the slowing down of the car or train inapproaching a station. or stopping oint may-commence at a point closerto t e station or stopping point than'has heretofore been the case orcustom in practice. In other Words with the use of the apparatusembodying my inventibn the car or train will be brought to a stop with'absolutenniformity and smooth ness in the minimum time and distanceafter the application of the brake mechanism,

7 thereby not onlyavoiding danger of disaster or injury resulting in atoo sudden or powerful application of the brake mechanism, but alsogreatly reducing' the time required in coming to a stop. These areparticularly desirable characteristics of a brake control mechanism foruse on interurban, subway, elevated 01' surface street cars where it isdesirable with congested traffic to operate the trains or cars asclosely as possible together, or with the least-interval of spacebetween them, and as rapidly as possible, in order. to secure rapidtransit of heavy or congested passenger traflic. Moreover, the danger ofserious or fatal accident through collision'is also largely reduced as acar or train can be stopped by the application of a control mechanismembodying the principles of my invention in the short- 1. In abrakemechanism for cars, the

combination with pressure supply controlhng devices, of actuatingdevices therefor,

' and means controlled conjointlyby the presv erases sure supplyand thespeed ofthe car for controlling said actuating devices.

2. In a brake mechanism for cars, the-- combination with "ressure sup lyand ex haust controlling. evices, of. .eectrical devices for operatingthe same, and means contrglled by the .speedof the car for controllingthe circuits of said electrical devices.

'3. In a brake mechanism for cars, the combination with a pressuresupply controllin valve and an independent exhaust controIling valve, ofmeans controlled by the speed of thecar for respectively controlling theoperation of said valves.

4. In a brake mechanism for cars, the

combination with pressure supply and exhaust controlling valves, ofmeans controlled conjointly by the pressure medium and the speed of theca'rfor respectively controlling the operation of said valves.

5. In a.brake mechanism for cars, the

combination with pressure supply, and ex-, haust controlling. valves, ofelectrical devices' for 0 erating said valves, and means controlled ythe speed of the car for controlling the circuits of said electricaldevices 6. In a brake mechanism for cars, the

combination with pressure supply and exhaust controlling valves, ofelectrical devices for operating said valves, and means controlledconjointly by, the pressure. medium' and the speed of the car forcontrolling .the,circuits of said electrical devices.

7. In a brake mechanism'for cars, the combination with respectivelyindependent pressure supply and exhaust controlling valves, of means foroperating the same, and means controlled conjointly by the speed of thecar and the pressure medium .for respectively controlling said operatingmeans.

8. In a brake mechanism forcars, th

combination with,pressure supply and exhaust controlling valves, ofmeans for operating the same, and means co'ntrolledby the conjointaction ofthe'pressure medium and the speed of the car for controllingsaid operating means;

9. In a brakemechanism for cars,"the combination with pressure supplyand exhaust controlling devices, of means for con-.

trolling saiddevices, said means including coeperatingcontacts,respectively controlle by the pressure supply and the speed of thecar.'--. 1 10. In a brake mechanism to cars, the combination withressure sup y and ex haust controlling evices and e ectricalde-,

. vices ton-"operating the-same, of meansfor controlling the circuits ofsaid electrical devices,"said means including a contact device arrang Ispeed ofhe can 11. In a ,brakemechanism? for: cars the combination withpressure supply "and exmeans therefor includin haust controllin to bemoved proportionately to the haust controlling devices of means foroper-- ating thesame'alternately according to the speed of the car. 7 a12. In a brake mechanlsm for cars, the

combination with respectivelyindependent pressure supply and exhaustcont'rollingfde vices, of means for operating the same alternately, saidoperating means being con: trolled conjointl and the speed 0 the car.

- 13. In. a brake mechanism for cars, the Q.

combination with pressure supply and ex haust controlling devices, andmeans for by the pressure medium operating the same, of'means forcontrolling said operating means, including-a contact arranged to bedisplaced in proportion to I the speed of the car, and a coiiperatingcontact arranged to be'displaced 1n.-proport'ion to the pressureapplied. I

14. 1n a brake mechanism for cars, the combination with pressure su plyand ex haust cont-rolling devices, 0% controlling means therefor, andincluding coeperating controlling the same including a rotatable diskcarrying contacts, a lever carrying a cooperating contact, said. diskarranged to displaced proportionately to 'the speed 0 X the car, aplston connected to be rotativel the lever, and acted u on on one sideby the pressure supply' to t e brake mechanism, and yielding meansacting upon the other side of said piston. I

17. In a brake mechanism for cars the combination with ressure supplyand ex haust controlling evices, of operating devices therefor and meansfor controlling the operating devices includin coiiperating de-- vicesrespectively operate by the ressu're supply'and the speed of the car, ana control-handle cotiperating with said last'named devices.

'controllin contacts, said disk arranged to be 181 In a brake 1mechanism for cars the I combination with evices, and e ectrical devicesfor control ing the same, of means for controlling the electricaldevices including coiiperating movable contacts-respectively operated bythe pressure sup ly and thespeed of the car, and a contro ndle forcompleting circuit to saidcontacts. I

ressure sup ly an ex 19. In a brake inechanism for cars; the

' combination with pressure supply and ex 'manually controlling thecircuits of said electrical means, and automatic-means, controlled bythespeed of the carfor controlling said circuits.

20 111 a brake mechanism for cars, the. combination with pressure supplyand ex-.

, haust controlling devices, and electrical means for operating thesame, of a manually operated handle for controlling the circuits of saidelectrical means, and relatively movable .contacts also controlling saidcircuits,-

said movable contacts operated respectively by the speed of the car andthe pressure f medium.

In testimony whereof lhave hereunto set my hand in the presence of thesubscribing w tnesses, on this 7th day of January A. D.

, HAROLD ROWNTREE. Witnesses:

D. SELOV'ER', M. H. MARTIN.

